Pneumatic tool having clockwise and counterclockwise rotation function

ABSTRACT

A pneumatic tool includes a housing, an air cylinder disposed in the housing, a valve unit, and a controlling unit. The air cylinder has an outer surface formed with a valve seat. A rotary valve of the valve unit is rotatable to allow compressed air to flow into the air cylinder through a selected one of first and second passages to thereby produce clockwise or counterclockwise rotation of the tool. The controlling unit includes a movable pin operable to move in the housing to drive rotation of the rotary valve. Preferably, the valve unit is disposed on the housing in a manner that the space occupied thereby in the housing is reduced.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 100146185,filed on Dec. 14, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a pneumatic tool, and more particularly to apneumatic tool having clockwise and counterclockwise rotation function.

2. Description of the Related Art

Referring to FIGS. 1 and 2, a pneumatic tool 1 disclosed in TaiwanesePatent No. I319346 includes a housing 11, an air cylinder 12 disposed inthe housing 11 and centered at an X-axis, a tubular air-guiding retainer13, a rotary valve 14, a pin 15, and a trigger unit 16. The housing 11has a handle 111, and has an intake passage 112 formed in the handle 111and connected to a compressed air source (not shown). The air cylinder12 has a cylinder wall 121 centered at the X-axis and defining an airchamber 120, as well as first and second passages 122, 123 for guidingair into the air chamber 120. The air-guiding retainer 13 is disposed inthe housing 11, extends along a direction parallel to the X-axis, and isin fluid communication with the first and second passages 122, 123. Therotary valve 14 is rotatable about the X-axis in the air-guidingretainer 13, is in fluid communication with the intake passage 112, andhas first and second outlets 141, 142. The pin 15 extends into thehousing 11 along a Y-axis, and is operable to move in the housing 11 todrive rotation of the rotary valve 14. The trigger unit 16 is disposedpivotally on the handle 111, and is operable to allow compressed air toflow into the intake passage 112.

As such, the rotary valve 14 is rotated by the pin 15 between a firstposition whereat the first outlet 141 is in fluid communication with thefirst passage 122 so that compressed air flows into the air chamber 120via the first passage 122 to drive clockwise rotation of the pneumatictool 1, and a second position whereat the second outlet 142 is in fluidcommunication with the second passage 123 so that compressed air flowsinto the air chamber 120 via the second passage 123 to drivecounterclockwise rotation of the pneumatic tool 1.

Since the air-guiding retainer 13 and the rotary valve 14 are arrangedalong the direction parallel to the X-axis, they occupy a relativelylarge space in the housing 11. Furthermore, such an arrangement of theair-guiding retainer 13 and the rotary valve 14 increases largely thewidth of the handle 111, thereby resulting in difficulties in grippingthe handle 111.

Further, since the angle formed between the intake passage 112 and thecentral axes of the air-guiding retainer 13 and the rotary valve 14 isapproximate to 90 degrees, compressed air cannot flow smoothly from theintake passage 112 into the air cylinder 12.

SUMMARY OF THE INVENTION

The object of this invention is to provide a pneumatic tool havingclockwise and counterclockwise rotation function, which can reduce thespace occupied in a housing by a valve unit and which allows smooth flowof compressed air from an intake passage into an air cylinder.

According to this invention, a pneumatic tool includes a housing, an aircylinder, a valve unit, and a controlling unit. The housing has anintake passage adapted to be connected with a compressed air source. Theair cylinder is disposed in the housing, and includes a cylinder wallcentered at an X-axis and defining an air chamber, a valve seat centeredat a Z-axis perpendicular to the X-axis and connected to the cylinderwall, a first passage, and a second passage. The first and secondpassages are formed in the cylinder wall, and are in fluid communicationwith the air chamber and the valve seat. The valve unit includes arotary valve that is disposed in the valve seat and that has anintermediate passage. The rotary valve is rotatable about the Z-axisbetween a first position whereat the intermediate passage is in fluidcommunication with the first passage in the air cylinder, and a secondposition whereat the intermediate passage is in fluid communication withthe second passage in the air cylinder. The controlling unit includes amovable pin disposed movably on the housing and operable to move in thehousing along a Y-axis perpendicular to the X-axis and the Z-axis tothereby drive rotation of the rotary valve.

Since the rotary valve is rotatable about the Z-axis, the space occupiedin the housing by the valve unit is reduced significantly, andcompressed air can flow smoothly from the intake passage into the aircylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of this invention will becomeapparent in the following detailed description of a preferred embodimentof this invention, with reference to the accompanying drawings, inwhich:

FIG. 1 is a fragmentary exploded perspective view of a conventionalpneumatic tool disclosed in Taiwanese Patent No. I319346;

FIG. 2 is a fragmentary, partly sectional side view of the conventionalpneumatic tool;

FIG. 3 is an exploded perspective view of the preferred embodiment of apneumatic tool having clockwise and counterclockwise rotation functionaccording to this invention;

FIG. 4 is a fragmentary, partly sectional perspective view of thepreferred embodiment, illustrating an air cylinder and a valve unit;

FIG. 5 is an exploded perspective view of the air cylinder and acontrolling unit of the preferred embodiment;

FIG. 6 is an assembled perspective view of the preferred embodiment;

FIG. 7 is a sectional view taken along Line VII-VII in FIG. 6;

FIG. 8 is a sectional view taken along Line VIII-VIII in FIG. 6; and

FIG. 9 is a sectional view taken along Line IX-IX in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3, 4, 5, and 6, the preferred embodiment of apneumatic tool having clockwise and counterclockwise rotation functionaccording to this invention includes a housing 2, a driving unit 3, anair cylinder 4, a rotor unit 5, a valve unit 6, and a controlling unit7.

The housing 2 has a front seat 21 and a rear seat 22 connected to thefront seat 21 along an X-axis. The rear seat 22 includes a housing body221, a handle 222 connected to and extending inclinedly along thehousing body 221, an exhaust passage 223 (see FIG. 7) formed in thehandle 222 and in fluid communication with the housing body 221, and anintake passage 224 formed in the handle 222 and in fluid communicationwith a compressed air source (not shown).

The driving unit 3 is mounted to the front seat 21 of the housing 2 foroutputting kinetic energy.

The air cylinder 4 is disposed in the rear seat 22 of the housing 2, andincludes a cylinder wall 41 centered at the X-axis and defining an airchamber 41, a valve seat 42 centered at a Z-axis perpendicular to theX-axis and connected to the cylinder wall 41, first and second passages43, 44 formed in the cylinder wall 41 and in fluid communication withthe air chamber 40 and the valve seat 42, and a projection 45 formed onthe cylinder wall 41 and adjacent to the valve seat 42. The valve seat42 has a first opening 421 formed at a side thereof, and a secondopening 422 (see FIG. 7) formed at an opposite side thereof.

The rotor unit 5 is disposed rotatably in the air chamber 40, and isco-rotatable with the driving unit 3.

The valve unit 6 includes a rotary valve 61 rotatable about the Z-axisin the valve seat 42, an air-guiding retainer 62 disposed removably onthe valve seat 42 for confining the rotary valve 61 in the valve seat42, and an air-guiding tube 63. The rotary valve 61 has a plurality ofteeth 611 centered at the Z-axis, formed on an outer surface thereof,and exposed in the first opening 421. The rotary valve 61 further has anintermediate passage 612 in fluid communication with the intake passage224, and a selected one of the first and second passages 43, 44, and anotch 613 in fluid communication with the second opening 422. Theair-guiding tube 63 has an inclination angle with respect to the Z-axis,and is in fluid communication with the intermediate passage 612 and theintake passage 224.

The controlling unit 7 includes a movable pin 71, a pushing member 72, apositioning member 73, and a resilient member 74. The movable pin 71 ismovable in the housing body 221 of the housing 2 in a Y-axisperpendicular to the X-axis and the Z-axis, and has a hole 711 formedtherethrough. The pushing member 72 is disposed between the rotary valve61 and the movable pin 71 along the X-axis, and has a rack 721 formed atan end thereof and engaging the teeth 611, and an engaging portion 722formed at an opposite end thereof. The pushing member 72 is obstructedby the projection 45 to maintain engagement between the rack 721 and theteeth 611. The positioning member 73 has an engaging portion 731inserted fittingly into the engaging portion 722 of the pushing member72, and an intermediate portion extending through the hole 711 of themovable pin 71. The resilient member 74 is disposed in a recess 732 ofthe positioning member 73, and has two ends abutting respectivelyagainst the front seat 21 and the positioning member 73 for biasing theengaging portion 731 of the positioning member 73 to move along thedirection parallel to the X-axis so as to engage the engaging portion722 of the pushing member 72, thereby allowing for synchronous movementof the movable in 71, the pushing member 72, and the positioning member73 along the Y-axis.

Referring to FIGS. 3, 8, and 9, to switch rotational direction of thedriving unit 3, it is only necessary to push the movable pin 71 to moveleftwardly or rightwardly along the Y-axis so that, due to engagementbetween the engaging portions 722, 731 of the pushing member 72 and thepositioning member 73, the rotary valve 61 can be rotated to the firstor second position.

When the rotary valve 61 is at the first position, compressed air flowsfrom the intake passage 224 into the air chamber 40 via a path includingthe intermediate passage 612 and the first passage 43, to thereby rotatethe rotor unit 5 and, thus, the driving unit 3 in a rotational direction(e.g., clockwise direction). At the same time, since the notch 613 is influid communication with the second passage 44, air flows from the airchamber 40 into the exhaust passage 223 via a path including the secondpassage 44, the notch 613, and the second opening 422.

When the rotary valve 61 is at the second position, compressed air flowsfrom the intake passage 224 into the air chamber 40 via a path includingthe intermediate passage 612 and the second passage 44, to therebyrotate the rotor unit 5 and, thus, the driving unit 3 in an oppositerotational direction (e.g., counterclockwise direction). At the sametime, since the notch 613 is in fluid communication with the firstpassage 43, air flows from the air chamber 40 into the exhaust passage223 via a path including the first passage 43, the notch 613, and thesecond opening 422.

In view of the above, the pneumatic tool of this invention has thefollowing advantages:

-   1. Since the rotary valve 61, the air-guiding retainer 62, and the    air-guiding tube 63 are arranged along the Z-axis, the space    occupied thereby in the housing 2 along the X-axis is reduced    significantly. In addition, the width of the handle 222 along the    X-axis is also reduced, so that the handle 222 can be gripped with    ease, thereby facilitating smooth operation of the pneumatic tool.-   2. Since the rotary valve 61 is rotatable about the Z-axis, the    angle formed between the intermediate passage 612 of the rotary    valve 61 and the intake passage 224 is relatively small, which    allows for smooth flow of compressed air from the intake passage 224    into the air cylinder 4 through the intermediate passage 612 to    promote effectively the driving force of the rotor unit 5.

With this invention thus explained, it is apparent that numerousmodifications and variations can be made without departing from thescope and spirit of this invention. It is therefore intended that thisinvention be limited only as indicated by the appended claims.

I claim:
 1. A pneumatic tool comprising: a housing having an intakepassage adapted to be connected with a compressed air source; an aircylinder disposed in said housing and including a cylinder wall centeredat an X-axis and defining an air chamber, a valve seat centered at aZ-axis perpendicular to said X-axis and connected to said cylinder wall,a first passage, and a second passage, said first and second passagesbeing formed in said cylinder wall and being in fluid communication withsaid air chamber and said valve seat; a valve unit including a rotaryvalve that is disposed in said valve seat and that has an intermediatepassage, said rotary valve being rotatable about said Z-axis between afirst position whereat said intermediate passage is in fluidcommunication with said first passage in said air cylinder, and a secondposition whereat said intermediate passage is in fluid communicationwith said second passage in said air cylinder; and a controlling unitincluding a movable pin disposed movably on said housing and operable tomove in said housing along a Y-axis perpendicular to said X-axis andsaid Z-axis to thereby drive rotation of said rotary valve.
 2. Thepneumatic tool as claimed in claim 1, wherein said valve unit furtherincludes an air-guiding retainer disposed removably on said valve seatso as to confine said rotary valve in said valve seat.
 3. The pneumatictool as claimed in claim 2, wherein said valve unit further includes anair-guiding tube connected to said air-guiding retainer and in fluidcommunication with said air-guiding retainer and said intake passage insaid housing.
 4. The pneumatic tool as claimed in claim 1, wherein saidvalve seat has a first opening formed at a side thereof, and said rotaryvalve further has a plurality of teeth formed on an outer surfacethereof and exposed in said first opening in said valve seat, saidcontrolling unit further including a pushing member engaging said teethof said rotary valve and connected to said movable pin.
 5. The pneumatictool as claimed in claim 4, wherein said pushing member is disposedbetween said rotary valve and said movable pin along said X-axis, and isformed at an end thereof with a rack engaging said teeth of said rotaryvalve, and formed at an opposite end thereof with an engaging portionthat is connected to said movable pin.
 6. The pneumatic tool as claimedin claim 5, wherein said air cylinder further includes a projectionformed on said cylinder wall and adjacent to said seat valve, saidprojection obstructing said pushing member so as to maintain engagementbetween said rack and said teeth.
 7. The pneumatic tool as claimed inclaim 5, wherein said controlling unit further includes a positioningmember, said movable pin having a hole formed therethrough, saidpositioning member having an engaging portion and an intermediateportion extending through said hole in said movable pin, one of saidengaging portions of said positioning member and said pushing memberbeing inserted fittingly into the other of said engaging portions ofsaid positioning member and said pushing member.
 8. The pneumatic toolas claimed in claim 7, wherein said housing further has a front seat anda rear seat connected to said front seat along said X-axis, said rearseat including a housing body for receiving said air cylinder, saidvalve unit, and said controlling unit, and a handle connected to saidhousing body and formed with said intake passage, said controlling unitfurther including a resilient member disposed between said positioningmember and said front seat for biasing said engaging portion of saidpositioning member to engage said engaging portion of said pushingmember.
 9. The pneumatic tool as claimed in claim 8, wherein said rearseat further includes an exhaust passage, said valve seat further havinga second opening formed at an opposite side thereof and in fluidcommunication with said exhaust passage, said rotary valve furtherhaving a notch in fluid communication with said second opening, saidnotch being in fluid communication with said second passage in said aircylinder when said rotary valve is at said first position, and with saidfirst passage in said air cylinder when said rotary valve is at saidsecond position.